Soil erosion is a phenomenon which occurs in a wide variety of situations. Erosion is accelerated by the action of wind and rain and is particularly troublesome in conditions of poor soil coherence. Land which has no ground cover, and particularly sloped land, will not retain the seeds of plants that might germinate to provide a root system to hold the soil in place. In such situations, rain storms fashion streams of water which carry away the seeds as well as the surface soil.
In the reclaiming of land from strip mine areas, inevitably large areas of soil entirely devoid of ground cover are created. In order to make such land attractive, it is frequently sloped, which aggravates the erosion problem. Further, the formation of highways and roads requires the making of cuts, embankments, culverts and the like which involve steeply sloped bare soil which is exposed to weather and prone to erosion if not stopped.
In order to apply seed and fertilizer rapidly, it is customary to spray aqueous slurries of seed, fertilizer and other nutrients on soil to be reclaimed. It is also common to distribute a layer of straw, by hand, over the surfaces of soil which have been thus planted. However, straw is susceptible to loss by wind and rain, and has proven to be ineffective on sloped surfaces. The prior art has proposed the use of a wide variety of materials to hold the straw in place, such as asphalt emulsions and the like. Various binding systems are proposed in the prior art, including U.S. Pat. No. 3,292,307, U.S. Pat. No. 3,482,353, U.S. Pat. No. 3,696,559, and Re. Pat. No. 28,950.
Further, the prior art has described mulch systems produced from cellulosic fibers, such as U.S. Pat. Nos. 3,017,720 and 3,165,862. These patents describe a mulch which comprises straw or other similar material which is adhered together using asphalt as an adhesive. While many of the compositions described in the prior art have been successful in producing mulch compositions satisfactory to accomplish a re-seeding of soil, such compositions, as a practical matter, have not been adapted to spraying.
Portable equipment which is adapted to spray aqueous slurries of seed and fertilizer and methods of spraying are described in the prior art, including U.S. Pat. Nos. 2,789,399, 2,842,897, 2,878,617, 3,091,436, and 3,292,307. The equipment described by the prior art is adapted to spray aqueous suspensions of finely divided cellulostic matter, chiefly chopped or cut-up cardboard and paper stock mixed with seeds and fertilizer to produce a mulch. The advantage of such equipment is its ability to spray the mulch on relatively inaccessable places which are not adapted to hand placement of the mulch.
The prior art, however, has failed to provide a hydromulch wherein the mulch, the seed, fertilizer, and lime necessary to support the growth of vegetation can be applied in a single operation. The prior art has relied, in general, on the hand application of hay or straw to provide the necessary mulch.